Saying you do Chin Na (Kahm Na in Cantonese) is like saying "I do punching"... it is a skill set, part of pretty much all TCMA. Misused and abused and frequently to absurd extremes. If I sit there while you stick needles in my eyes, yeah it will hurt, but who is going to sit there?

I trained for 3 years with a chin-na specialist, and while he had a bewildering number of locks and some very interesting reversals and escapes, the underlying problem was always the same: why the hell am I grabbing some guy's wrist, and just standing there while he goes through his lock?

I'll bite: these are all things I've been subjected to and they hurt and can potentially break joints and whatnot, but to damage the joints there needs to be a great degree of control over the joint (thus, most MMA matches won by joint locks are on the ground). The locks in the videos are targeting the joints that are the easiest to flail and thrash out of, because they're at the end of your arms. Also they require you to stand inside punching range and use both hands to immobilize one of theirs. He tries to negate this by stepping to the outside etc, but it can be a rude awakening when you're trying to apply something and someone smacks you in the face.

Video #1: techniques where you flex the elbow inward and upward to get a shoulder lock while standing are difficult against real people. If anything real people tend to flex their arms outward intuitively. Also, weird choice of technique to break his posture afterwards.

Video #2: same comments apply, and the starting grip position is laughably easy to escape from.

Video #3: in the amount of time it takes to do a semicircular parry, a real person will probably retract the arm, because holding an arm out there like that isn't good sense for anyone. Likewise, when you put someone's wrist in an awkward position but all they have to do is let you go, people let go and try for something else.

this is going to come across as rude, but heck, why not just continue... I spent in excess of 20 years doing TCMA with some well known (and not well known) teachers, "chin na specialist" almost always mean someone with no real style/system, making it up as he goes along

Do we have punching specialists or kicking specialists? How about "foot sweeps with only the left foot" specialists?

Crap like this (and the videos) are why no one respects "kung fu" and rightly so IMHO